A system is disclosed for restoring a surface field potential of an electret material. An oscillator generates an oscillating output, and a power amplifier amplifies the oscillating output. A step-up transformer generates a high voltage alternating current output from the amplified oscillating output, and a polarity controller generates one of a positive pulsating output and a negative pulsating output from the high voltage alternating current output.

A system is disclosed for restoring a surface field potential of an electret material. An oscillator generates an oscillating output, and a power amplifier amplifies the oscillating output. A step-up transformer generates a high voltage alternating current output from the amplified oscillating output, and a polarity controller generates one of a positive pulsating output and a negative pulsating output from the high voltage alternating current output.

An embodiment of the disclosure provides an electronic device including a power supply, an optical to electrical converter and a controller. The power supply outputs a first electric power. The optical to electrical converter receives an infrared light beam and converts the infrared light beam to a second electric power. The controller is coupled to the power supply and the optical to electrical converter. The controller operates in a first mode and a second mode. When the controller operates in the first mode, the controller is activated by the second electric power and after the controller is activated, the controller operates in the second mode and drives the power supply. Then, the controller receives the first electric power and stops receiving the first electric power for operation.

An embodiment of the disclosure provides an electronic device including a power supply, an optical to electrical converter and a controller. The power supply outputs a first electric power. The optical to electrical converter receives an infrared light beam and converts the infrared light beam to a second electric power. The controller is coupled to the power supply and the optical to electrical converter. The controller operates in a first mode and a second mode. When the controller operates in the first mode, the controller is activated by the second electric power and after the controller is activated, the controller operates in the second mode and drives the power supply. Then, the controller receives the first electric power and stops receiving the first electric power for operation.

A driving circuit and a driving method are provided. The driving circuit includes a power stage circuit and a full-bridge circuit. The power stage circuit is configured to receive an input voltage, and generate an output voltage at an output port of the power stage circuit. The full-bridge circuit is coupled to the output port of the power stage circuit and is configured to perform charging and discharging on a piezoelectric load. An operating mode of the full-bridge circuit is controlled, so that a supply voltage signal for driving the piezoelectric load during a first operating interval of an operating cycle corresponds to a reference voltage in a first interval, and the supply voltage signal during a second operating interval of the operating cycle corresponds to the reference voltage in a second interval. The driving circuit has a small volume, which is conducive to circuit integration.

An electrical converter chosen from the group consisting of an inverter able to generate an AC voltage from a DC voltage and a rectifier able to generate a DC voltage from an AC voltage. This converter comprises a first inductor and a controllable switch that are connected in series between first and second DC voltage ports. The converter comprises a piezoelectric resonator comprising: a first electrode connected directly to a first power terminal of the switch, a second electrode connected directly to a second power terminal of the switch, and a piezoelectric material interposed between the first and second electrodes.

An electrical converter chosen from the group consisting of an inverter able to generate an AC voltage from a DC voltage and a rectifier able to generate a DC voltage from an AC voltage. This converter comprises a first inductor and a controllable switch that are connected in series between first and second DC voltage ports. The converter comprises a piezoelectric resonator comprising: a first electrode connected directly to a first power terminal of the switch, a second electrode connected directly to a second power terminal of the switch, and a piezoelectric material interposed between the first and second electrodes.

A technique for performing power level control of one or more beams transmitted by a wireless transmission device to a wireless reception device is disclosed. A method implementation of the technique is performed by the wireless transmission device and comprises transmitting (S202) each of the one or more beams at a default power level of the respective beam, detecting (S204) an obstacle entering the one or more beams based on a change in an electromagnetic environment associated with the one or more beams, the obstacle, once entered, at least partially blocking the one or more beams with respect to the wireless reception device, and decreasing (S206), for each of the one or more beams, an output power of the respective beam from the default power level of the respective beam to a predetermined threshold power level of the respective beam.

A technique for performing power level control of one or more beams transmitted by a wireless transmission device to a wireless reception device is disclosed. A method implementation of the technique is performed by the wireless transmission device and comprises transmitting (S202) each of the one or more beams at a default power level of the respective beam, detecting (S204) an obstacle entering the one or more beams based on a change in an electromagnetic environment associated with the one or more beams, the obstacle, once entered, at least partially blocking the one or more beams with respect to the wireless reception device, and decreasing (S206), for each of the one or more beams, an output power of the respective beam from the default power level of the respective beam to a predetermined threshold power level of the respective beam.

Current sharing among bidirectional double-base bipolar junction transistors. One example is a method comprising: conducting current through a first bidirectional double-base bipolar junction transistor (first B-TRAN); conducting current through a second B-TRAN the second B-TRAN coupled in parallel with the first B-TRAN; measuring a value indicative of conduction of the first B-TRAN, and measuring a value indicative of conduction of the second B-TRAN; and adjusting a current flow through the first B-TRAN, the adjusting responsive to the value indicative of conduction of the first B-TRAN being different than the value indicative of conduction of the second B-TRAN.